**Reason**
[[ https://www.mediawiki.org/wiki/Extension:Semantic Tasks | Extension ]] unmaintained for years which will be taken over and further developed on [[ https://github.com/SemanticMediaWiki/SemanticTasks | GitHub ]].
**To-do list**
- This task
-- [x] Add maintainers of that extension as subscribers to this task (if they have no apparent Phabricator account, notify them on-wiki or via email if possible and note it here).
-- [x] Clone the existing repo into the new repo
- Phabricator
-- [x] ~~Archive Phabricator project <#ProjectX> for the extension.~~
-- [x] Mark all Phabricator tasks for the extension either Declined or Invalid.
-- [x] ~~Edit Phabricator project <#ProjectX> description for the extension/skin with a link to this ticket.~~
- Translatewiki.net/translations
-- [x] Switch `translatewiki.net` from Gerrit to GitHub (`groups/MediaWiki/mediawiki-extensions.txt`) (add #translatewiki.net project as a tag for this task).
- Configuration/tests/integrations/etc.
-- [ ] Remove from `mediawiki/extensions` / `mediawiki` (along with in `.gitmodules`).
-- [ ] Remove tests in [[ https://gerrit.wikimedia.org/g/integration/config | `integration/config` ]] (`zuul/layout.yaml`) -- [[ https://gerrit.wikimedia.org/r/c/integration/config/+/567262 | I23a2f4deec7b2 ]].
-- [x] Remove manifest/other references from `mediawiki/vagrant` if they exist.
-- [x] Remove from https://doc.wikimedia.org/cover-extensions/ if present (requires #continuous-integration-infrastructure shell user to delete directly from the server).
- Repositories
-- [ ] Empty repository leaving only the README indicating the repo has moved to the new repo and referring to this task by URL -- [[ https://gerrit.wikimedia.org/r/c/mediawiki/extensions/SemanticTasks/+/567273 | Ie126283cd124e1560ac ]].
-- [ ] Mark the repository read-only in Gerrit (Edit description to prepend "[MOVED]" and append Task reference): (https://gerrit.wikimedia.org/g/mediawiki/extensions/SemanticTasks).
-- [ ] Configure repository for the extension/skin: ({rESTA}) to watch GitHub upstream instead.